title: Synthesis of heterostructured helical carbon nanotubes by iron-catalyzed ethanol decomposition.
abstract: Shaping of carbon nanotubes (CNTs) into desired morphologies have attracted much attention recently. High quality heterostructured helical carbon nanotubes (HCNTs) were synthesized from transitional metal oxide and ethanol by chemical vapor deposition (CVD) in this paper. High resolution transmission electron microscopy (HRTEM) results showed that, heterostructured "U" shape, "G" shape and "S" shape HCNTs were achieved. Iron oxide was reduced to α-Fe by ethanol, and catalyzed the growth of heterostructured HCNTs. Helical coiling of HCNTs was induced by the anisotropic facet catalytic activity of α-Fe catalyst for carbon deposition. Then, symmetrical growth of two HCNTs from one catalyst nanoparticle resulted in symmetrical "U" shape HCNTs, while successive connecting of several "arc" and "tail" HCNTs led to asymmetrical "G" and "S" morphologies HCNTs.
authors.affiliation: School of Materials Science and Engineering, Dalian Jiaotong University, 116028 Dalian, PR China. Zhangyong0411@126.com
authors.forename: Zhang
authors.initials: Z
authors.lastname: Yong
authors.forename: Liu
authors.initials: L
authors.lastname: Fang
authors.forename: Zhang
authors.initials: Z
authors.lastname: Zhi-hua
mesh_terms: D002384:Catalysis; D000431:Ethanol / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D037742:Nanotubes, Carbon; C000499:ferric oxide; D000431:Ethanol; D007501:Iron